350 SURVEY OP THE COAST 



45. Two beam compasses, vviih short and lon^ rods, and 

 a double set of points, and one set to work upon brass, by 

 Fidler. 



46. Three proportional compasses, with perpendicular 

 legs, for reduction and for constructing maps, by Fidler. 



47. Two steel rules, live feet long and four inches broad, 

 and four steel triangles of two sizes, to use with them by 

 Fidler. 



48. Various duplicate parts, to replace accidental loss or 

 breakage ; as turnscrews, metal wire, spirit level tubes tilled, 

 dark glasses, magnifiers, barometer tul)es, Sjc. 



49. The books consist of the best and most recent works 

 on astronomy and geodesy, particularly useful for the in- 

 struction of the young officers intended to be employed in 

 the work, — the newest astronomical and logarithmic tables 

 of different kinds, — catalogues of the fixed stars, and celestial 

 atlasses, — some other works of interest for the observatory, 

 — the French Connaissance des Tems for several years, — in 

 the whole forty -five works, of many of which duplicates were 

 provided. 



Comparison of the French and English Standard Measures 

 of Length, and Regulation of the Bars for the Base Line 

 ApiHiratus. 



The necessity of having a standard measure of length, as 

 accurate and as authentic as possil)le, for the measurement 

 of the base lines, is suff^iently evident to shew the propri- 

 ety of all the care which was taken to attain this object. 



The two measures of leni»;th which have been the most 

 scientifically ascertained and compared, are the French and 

 English. 



They are essentially different in their principle, and of 



